1. Field of the Invention
Embodiments of the invention relate to an organic light emitting diode (OLED) display.
2. Description of the Related Art
An organic light emitting element used in an organic light emitting diode (OLED) display has a self-emission structure in which a light emitting layer is formed between two electrodes on a substrate. The OLED display may be classified into a top emission type OLED display, a bottom emission type OLED display, and a dual emission type OLED display depending on an emitting direction of light. The OLED display may be classified into a passive matrix type OLED display and an active matrix type OLED display depending on a driving manner.
In the OLED display, each of a plurality of subpixels includes a transistor unit and a light emitting unit. The transistor unit includes a switching transistor, a driving transistor, and a capacitor, and the light emitting unit includes a lower electrode connected to the driving transistor, an organic light emitting layer, and an upper electrode. When a scan signal, a data signal, a power, etc. are supplied to the plurality of subpixels arranged in a matrix form, the selected subpixels emit light to thereby display an image.
In the OLED display, a contact electrode is formed in a non-display area so as to supply a power to upper electrodes of the subpixels formed in a display area. Further, the contact electrode is electrically connected to the upper electrode in a formation process of the upper electrode. However, in a related art OLED display, a smooth contact between the contact electrode formed in the non-display area and the upper electrode formed in the display area is not achieved, and a short circuit between the contact electrode and the upper electrode is generated. Further, the contact electrode may be damaged because of a concentration of an electric filed on an upper edge of the contact electrode.